Insecticide-treated bags

ABSTRACT

Plastic bags, especially polyethylene bags, coated or impregnated with an organophosphorus insecticide, especially pirimiphos methyl. The pirimiphos methyl has a vapor pressure at 20* C in the range 1 X 10 3 -1 X 10 6 millimeters of mercury, and is used in an amount of 1 to 100 m.g. of the insecticide per square foot of bag surface.

Umted States Patent 1191 1111 3,771,254

Scott et a1. Nov. 13, 1973 [54] INSECTICIDE-TREATED BAGS 3,094,8056/1963 Luck 43/131 3,653,145 4/1972 Stout 43/131 [75] lnvemmsscmDatchwmth 2,139,040 12/1938 Salfisberg 43/131 ux flefffordshlre;Rogelj Tuso" Taylor, 3,630,446 12/1971 R6111 et a1. 43 131 x Mald n aBerkshlre, both of 3,032,915 5 1962 Giroud-Abel 43/131 England 3,605,3219/1971 Lazarus 43/131 3,156,355 11/1964 Rodgers..... 206/56 AA [73]Asslgnee= Imperial Chemm' lndusmes 3,304,646 2/1967 Staley 43/131Limited, London, England [22] Filed: Jan. 4, 1972 Primary ExaminerLouisG. Mancene Assistant Examiner-James H. Czerwonky [21] Appl' 215393Att0rneyCushman, Darby & Cushman [30] Foreign Application Priority DataJan. 6, 1971 Great 5116116 .1 660/71 ABSTRACT June 22, 1971 GreatBrltzun 29179/71 Plastic bags, especially p y y bags, coated or [52] usCl 43,131 43/12O 206/46 PV impregnated with an organophosphorusinsecticide, N 220265 424/200 especially pirimiphos methyl. Thepirimiphos methyl [51] Int Cl Aolm 1/10 b N20 has a vapor pressure at 20C in the range 1X10 [58] Field 43/l31l32 R 120 l l0 millimeters ofmercury, and is used in an 206/56 AA amount of 1 to 100 m.g. of theinsecticide per square 220/65 2 foot of bag surface.

' 5 Claims, 3 Drawing Figures [56] References Cited UNITED STATESPATENTS 3,295,246 [/1967 Landsman et a1. 43/131 1 INSECTICIDE-TREATEDBAGS The present invention relates to bags and more par- I ticularly tobags made of flexible plastics sheet material. By the term bags weinclude sacks and the like, open or closed at either or both ends.

According to the present invention we provide a bag of flexible plasticssheet material coated or impregnated with an organo-phosphorusinsecticide.

FIG. 1 is a perspective view of a bag coated or impregnated according tothe present invention;

FIG. 2 is an enlarged fragmented section of an impregnated bag alongline 2-2 of FIG. 1; and

FIG. 3 is an enlarged fragmented section of a coated bag along line 2-2of FIG. 1.

Examples of suitable organophosphorus insecticides are DDVP, andpirimiphos ethyl. Particularly suitable organophosphorus insecticideshave a vapour pressure in the range 1 X 1 X 10' mm Hg at C. It isespecially preferred to use an organophosphorus insecticide of lowmammalian toxicity such as malathion or fenitrothion. The most preferredinsecticide for use in our invention is pirimiphos methyl, but diazinonis also very useful.

The bags of our invention may be made from any film-forming polymer,including polyvinyl chloride and copolymers thereof, e.g. withvinylidine chloride; polypropylene; polysulphones andpoly-4-methyl-pentene- 1. We particularly prefer to use low densitypolythene on account of its cheapness, wide use in the manufacture ofbags, and its permeability characteristics. Preferred grades ofpolyethylene for use in making bags have a Melt Flow Index (as measuredby ASTM test 1238/56) of 0.1 to 20, especially 0.3 to 2.0.

Bags according to our invention are preferably made by first forming theselected plastics material into flexible sheet and thereafter coating orimpregnating the sheet or parts thereof with the selected insecticide.The sheet may be formed into bags by welding or sticking ofappropriately shaped blanks either before or after the coating orimpregnation step. Sheet may be made by calendering, or by extrusion,preferably followed by drawing in one or more directions atright anglesto each other. The preferred method of making polyethylene into sheet orfilm is the well known bubble method in which a tube of polyethylene isextruded and thereafter caused to expand by the application of internalair pressure to form a tubular bubble. The cooled tubular film may,after flattening, be sealed transversely at intervals of one bag length,and the separate bags severed from the length, or provided instead withlines of perforations or similar weakening by which they maysubsequently be separated from a reeled length of bags.

Coating or impregnation of the flexible plastics sheet material isgenerally done by treating it with a solution or dispersion containingthe insecticide. The rate at which insecticide is applied will generallybe within the range 1.0 -l00 mg. especially 4.0-20 mg.ft' of totalexterior surface, but greater or lesser amounts than this may be used,depending on the insecticide, the plastics material, and the use forwhich the bag is intended. It is preferred to treat the outside of thebag, or that surface of the flexible plastics sheet material whichsubsequently becomes the outside of the bag. This may be done, forexample, by passing the flattened tubular film continuously through abath of a solution or dispersion of the insecticide. It is preferablydone by applying the insecticide to the bag surface in a lacquer orprinting ink base. This lacquering or printing step is preferablycarried out before the tubular film is transversely sealed and severedto form bags. It is desirably preceded by some treatment to make theplastics surface more retentive to lacquer or printing, e.g. coronadischarge treatment.

It is not found generally necessary that the whole of the exterior ofthe bag be lacquered or printed, and it may not even be necessary totreat the whole of one side. Lacquer may be used to make the bag apleasing or distinctive colour; printing ink may be used to printindicia including trademarks, indications of the intended function ofthe bag and preferably also an indication of the presence of theinsecticide and precautions which should in consequence be observed.

It is a surprising feature of our invention that in favourablecircumstances, the application of insecticide to the exterior of a bagmay be effective to kill insects inside the bag.

Bags according to our invention find a variety of uses. For example theymay be used to hold refuse, e.g. as dustbin liners. When so used theymay have the effect of killing houseflies and like pests both in thedustbin and subsequently when the dustbin liner is removed to the refusetip. They may also be used for horticultural purposes; for example arose-bush heavily infested with aphids may be enveloped in a suitablebag according to our invention for 24 or 48 hours, resulting in rapiddeath of the aphids. Bags according to our invention may be used toenclose or package vegetables and fruit, e.g. dried beans; or bananas,both while still on the tree and while being transported to theconsumer.

In order to prevent loss of insecticide from the bag, with possible lossof effectiveness in use, it is preferable to make them available forsale packed in impermeable containers, either singly or in bulk. Thecontainer may be of rigid metal or be an envelope or wrapping of foil,e.g. aluminum foil, or a paper/foil laminate.

Pirimiphos methyl is the 881 approved common name for the compound2-diethylamino-6-methylpyrimidin-4-yl dimethyl phosphorothionate.

Pirimiphos ethyl is the BSI-approved common name for the compoundZ-diethylamino-6-methylpyrimidin- 4-yl diethyl phosphorothionate. Thefollowing Examples illustrate the invention.

EXAMPLE 1 Preformed rectangular transparent polyethylene bags, 100gauge, 14 sq. ft. in surface area, made by a bubble process fromAlkathene (Trade Mark) granules, of MP] 2 were used. These were openedout and attached to a metal frame. Their inside surfaces were thensprayed with solutions of pirimiphos methyl in industrial methylatedspirits, using an aerograph spray gun giving a very fine mist spray.Dilution rates were chosen to give application rates of insecticide offrom 5 to IOOmg/sq foot to 1,400 mg per bag). The bags were then leftopen for 5 minutes to allow the solvent to evaporate.

Bags so prepared were tested for insecticidal properties. 50 Adultl-louseflies (Musca domestica) were intro duced into each bag, the necktied and the bag suspended from a beam. The time taken to kill percentof the flies in each bag is shown in Table I below. This experiment wasrepeated at intervals over a period of 21 days, the bag being leftexposed to the atmosphere mg/sq throughout this time. A 10 1% A 2 -sits-2 24-21 Table l B l Fri-2 2%-2l B 2 -5 1 6-2 254-21 5 Applicationrate Days after unwrapping of insecticide Time in minutes to give 90%kill of bags 0 9 mg/sq foot I00 6 6 10 25 35 EXAMPLE 3 50 6 7 2s 60 9010 1a 30 120 120 22s 10 Preformed polyethylene bags of 220 gauge film 145 13 75 60 90 300 square feet in exterior surface area were subjected toDays after corona discharge treatment to make their surfaces g glz O l 7I4 21 more adhesive. The following printing ink formulation TABLE I]Application rate of insecticide Time in minutes to give90% kill mg/sqfoot 25 I00 IO 60 80 50 120 90 120 I0 180 390 300 5 120 390 300 Daysafter impregnation 7 i4 21 of bags EXAMPLE 2 Preformed bags of the typeused in Example 1 were treated on their exterior surfaces with solutionsof pirimiphos-methyl in isopropyl alcohol. Solutions containing theinsecticides were dripped onto each bag from a pipette and then smearedover an area of about 1 square foot by rubbing part of the exteriorsurface against itself. Two application rates were used: 0.2 ml. and 0.8ml. of an 18 percent solution, equivalent to 2.5 mg. and 10 mg./sq. footof total exterior bag surface. Finally each bag was folded and closelywrapped in 100 gauge aluminum foil.

Bags thus prepared were unwrapped at intervals and tested in the sameway as the bags of Example l. Resuits are shown in Table III and IVbelow. In Test A the flies are confined only by the bags; in Test B theyare in a muslin cage in the bag.

TABLE II Bags unwrapped 3 days after treatment Applicatittm ra 0,mg./sq.ft. Time in hours to give 90% kill TABLE IV Bags unwrapped 31days after treatment Test Application rate Time in hours to give killwas prepared.

pirimphos-methyl technical pure) 10% w/v solvent 20% printing ink W 13(orange) 70% Using a hand-operated printing roller, this ink was appliedas four strips each 3 inches X 30 inches down one face of the bag. Theapplication rate was varied by applying one, two or three coats of ink;each coat being allowed to dry before a further coat was applied. Threebags were coated at each rate; a rough indication of the amount ofinsecticide applied was obtained by weighing the sacks before and afterprinting. Finally, each sack was individually wrapped in 100 gaugealuminum foil.

Bag No. Approximate weight Insecticide on exterior gain/bag of bag(mg/sq foot) Bags were then tested by a modification of the methods usedin Example 1. Sacks were placed in refuse bag holders, having a wiremesh body and an open neck covered with a loose-fitting plastic lid.Simulated refuse, consisting of balls of newpaper and a food pad, wereplaced in each bag, together with 25 flies. The mortality of the flieswas assessed at intervals. Results are shown in Tables V and VI below.

EXAMPLE4 Tabular polyethylene film lOO gauge, prepared by a bubbleprocess from Alkathene of ME] 2 was corona discharge treated and thenpassed to a multi-stage printing press. The tube was printing on oneside with a continuous repeating pattern of interlocking circles, usinga printing ink formulation containing percent pirimiphos-methyl percentsolvent (fast) and 70 percent red printing ink. On the other side of thetube was printed at intervals the l C l Roundel (Trademark) and thelegend: 1 C l for Home and Garden Insecticidal Dustbin Liner. KillsFlies! WARNING Wash hands after touching this sack. Do not allow to comeinto contact with food. Keep away from children. The printing inkformulation used for this legend consisted of 10 percent pirimiphosmethyl, 20 percent solvent (slow) and 70 percent printing ink W13(orange). After printing, the tube was passed to a heat sealingapparatus, which formed lateral sealed zones at intervals across it; theresulting product was then laterally severed midway between the sealedzones to form sacks. Each sack was individually wrapped in 100 gaugealuminum foil.

percent of the total outer surface of the film. After printing, the filmwas cut into bags (open at both sides) 24 inches wide by 48 inches long:one end of each bag was then sealed. Each bag had the same area ofprinting on it. The sacks so formed were then individually wrapped in100 gauge aluminum film until required for use. Analysis one week latergave the results shown in Table VI] below.

To test insecticidal activity the bags were placed either as linersinside a plastic dustbin or in a wire mesh sack holder. Several sheetsof screwed-up newspaper a milky pad and lump sugar were placed insideeach suck to simulate waste. 25 house flies (Musca domestica) wereintroduced into the sacks and the open ends closely covered with nylongauze. Counts of the num ber of live flies visible were made atintervals over 24 hours. After emptying out the contents the sacks wereleft exposed to the atmosphere for 1 3 weeks before retesting in thesame way. Results of the tests, which are given in Table VII below, showthat all the treatments had a high insecticidal activity, with fourexceptions giving a complete kill of houseflies within 3 hours. Thisactivity showed a slight tendency to increase after exposure to theatmosphere for up to 3 weeks.

TABLE VII(A) Clear plastic sacks Coats of ink lirimiglhqs Number offlies alive after me y z I usecticidal Non-insecticidal Time of testrug/sack 1 hr 2 hrs. 3 hrs. 4 hrs. 24 hrs.

1 0 {Day unwrapped. 370 15 10 0 0 0 Exposed one week.... 370 15 2 1 0 01 0 {Day unwrapped. 390 13 10 3 0 0 Exposed one Week 390 15 0 t) 0 0 0{Day unwrapped. 1, 080 20 0 0 0 l) Exposed one week l, 080 8 O t) (l l)1 {Day unwrapped. 027 s a o o o Exposed one week... 027 15 0 0 0 U 0 0{Day unwrapped 0 20+ Exposed 1 week 0 20+ TABLE VII(B) Pigmented PlasticSacks Coats oiink Mg. pirimiphos Number of flies alive after IIlSec-Non-inseemethyl 7 ticidal tieidal Time of treatment per sack 1 hr. 2hrs. 3 hrs. 4 hrs. 5 hrs.

1 0 {Immediately unwrapped.... 400 20 12 1 0 0 Exposed three Weeks 40012 6 0 0 0 1 1 {Immediately unwrapped 450 15 6 1 0 0 Exposed three weeks450 12 2 0 O O 0 {Immediately unwrapped..-. 1,100 10 3 1 0 0 Exposedthree weeks 1, 100 8 0 0 0 O 2 1 {Immediately unwrapped.-. 927 12 8 2 00 Exposed three weeks 927 4 2 1 0 0 0 0 {Immediately unwrapped.-. 20+Exposed three weeks 20+ EXAMPLE 5 Bags were made on an in-line bagmaking machine, incorporating a three-stage printing press. Tubular 220gauge polyethylene film, both clear and pigmented, prepared by a bubbleprocess from Alkathene of MFP 2 was corona discharge treated and passedto the printing press. It was there printed with one or two coats of inkcontaining pirimiphos methyl (as used in' Example 3), in a pattern ofrectangular blocks applied to the exterior of the tubular film. In somecases a top coat of ink not containing insecticide was overprinted. Inall cases the printed area represented approximately EXAMPLE 6 foil.

Other sacks from the same batch were treated with several differentinsecticides as follows:

The insecticide was prepared as a 10 percent solution insolvent/printing ink (w 13) mixture. 2.0 g, 1.0 g or 0.5 g of solutionwere smeared over a portion of the outer surface of the sack, which wasthen left to dry for 10 minutes, and closely wrapped in aluminium foil.

All the sacks were then tested for insecticidal activity selected fromthe group consisting of polyvinyl chloride, polypropylene,polysulphones, poly-4 methylpentene-l and polyethylene and having aninterior surface, an exterior surface and two ends together forming acontainer of said flexible plastic sheet material, a portion of saidexterior surface having an adherent composition comprising pirimiphosmethyl insecticide, having a vapor pressure at 20 C in the rangelXl-1X10' millimeters of mercury, in an amount within the range asintExample 5. Results are shown in Table Vlll below. 10 of 1 to 100 mg.of said insecticide per square foot of TABLE VIII p Number of fliesalive afterplCSSilfG, Vtl'eight mm. g, o solu- Inseetieide 20 0 tion, g.Time of test hr. 1 hr. 2 hrs. 3 hrs. 5 hrs. 24 hrs Immediately alterunwrapping 0 0 0 0 0 0 Dichlorvos 1X10 2 {1 week after unwrpapping 20+20+ 20+ 20+ 0+ DD 1 0 {Immediately after unwrapping" 0 0 0 0 0 0weelaltef unwrapping-A. 3- 3' g 6* mme late y a rer unwrapping 0 DmzinonSAX) 5 0 {1 week after unwrapping 20 2 O 0 0 0 Do 1 0 {Immediately afterunwrapping 20 2 0 0 0 0 a t ez pp 28$ 8 g g mine iate y a er unwrapping"Femtwthwn 5X10 5 0 week after unwrapping 2g+ 20+ 1g 6) J g mmediate yafter unwrappingn. 0 6 Malathlon 13x10 4 0 {1 week after unwrapping 20+20+ 20+ 20+ Li da 2 0 {Immediately after unwrapping" 20+ 20+ 20+ 20+ 20+20+ Weelglfti unwrapping. 20 20+ 203- 203- l- M6 mme ate y afrerunwrapping- Plnlmphos methyl 1X10 4 0 {1 week after unwrapping 20+ 20 30 0 0 D0 1 0 {Immediately after unwrapping 20+ 12 0 0 0 0 r 1 week afterunwrapping 2 3 0 Seek pnnted wlth pinmiphos methyl (100 {Immediatelyafter unwrapping" 8 0 0 0 0 8- D 1 week alter unwrapping 0+ 3 0 0 0 0Untreat d k {Immediately after unwrapping" 20+ 20+ 20+ 20+ 20+ 20+ 1week after unwrapping 0+ 30+ said portion of said exterior surface.

2. A bag according to claim 1 which is open at both ends.

3. A bag according to claim 1 wherein said adherent compositioncomprises printing ink.

4. A bag according to claim 3 wherein said adherent composition isprinted on to said exterior surface so as to form indicia thereon.

5. A bag according to claim 1 which is packed in a vapor impermeablemetallic envelope.

2. A bag according to claim 1 which is open at both ends.
 3. A bagaccording to claim 1 wherein said adherent composition comprisesprinting ink.
 4. A bag according to claim 3 wherein said adherentcomposition is printed on to said exterior surface so as to form indiciathereon.
 5. A bag according to claim 1 which is packed in a vaporimpermeable metallic envelope.